Fire extinguishing system



Aug. 29, 1944- c. A. GETZ I 2,356,990

FIRE EXTINGUISHING SYSTEM Filed Nov. 28, 1942 s Sheets-Sheet 1 Zarl esAdeix Aug. 29, 1944. c. A. GETZ FIRE EXTINGUISHING SYSTEM Filed Nov. 28,1942 8 Sheets-Sheet 2 c. A. GETZ 2,356,990

FIRE mx'rmeuxsnme SYSTEM Filed Nov.- '28, 1942 a Sheets-Sheet 5 Aug. 29,1944.

Aug. 29, 1944. c. A. GETZ FIRE EXTINGUISHING SYSTEM Filed NOV. 28, 19428 Sheets-Sheet 4 fla rlesd- Gale Aug. 29, 1944. c, 5 2

FIRE EXTINGUISHING SYSTEM Filed Nov. 28, 1942 8 Sheets-Sheet 5 ZazlesAfieiz Aug. 29, 1944. c. A. GETZ 2,356,990

I FIRE EXTINGUISHING SYSTEM Filed Nov. 28, 1942 V 8 Sheets-Sheet 6 Aug.29, 1944. c. A. GETZ FIRE nxwmauxsnme SYSTEM Filed Ndv. 28. 1942 aSheets-Sheet '7 Aug. 29, 1944. GETz 2,356,990

FIRE EXTINGUISHING SYSTEM Filed NOV. 28, 1942 8 Sheets-Sheet 8 Elma/whomflax/21A dale Patented Aug. 29, 1944 FIRE EXTINGUISHING SYSTEM CharlesA. Getz, Glen Ellyn, IlL, assignor, by mesne assignments, toReconstruction Finance Corporation, Chicago, Ill., a corporation of theUnited States Application November 28, 1942,

23 Claims.

This invention relates to new and useful improvements in ilreextinguishing systems and deals more particularly with systems thatemploy liquid carbon dioxide as the extinguishing medium. and rate ofdischarge; and which may employ A relatively recent innovation in carbondioxide any total footage of piping that is required to fireextinguishing systems involves the use of a serve either a remotelylocated hazardor a numcentrally located, insulated tank for confiningber of closely grouped independent hazards, all liquid carbon dioxide ata controlled subatmoswith a minimum amount of trouble caused by pherictemperature and its corresponding low leakage, trapping of extinguishingmedium in vapor pressure; suitable piping for conducting portions of thepiping, etc. the liquid carbon dioxide to the several hazards A furtherobject of the invention is to provide that are to be protected, and asuitable number a fire extinguishing system in which the flow of ofvalves for controlling the flow of the liquid the extinguishing mediumfrom the central from the central tank to the one or more hazards sourceof supply to a hazard is controlled by at that are to be protected.least two normally closed valves which are ar- Systems of this type mayrequire the use of ranged in series in the piping with one valve eithera few hundred pounds or several tons of located relatively close to thesource of supply the liquid carbon dioxide to provide adequate so as tonormally exclude the high pressure liquid protection for the hazards,and an adequate rate from the piping and with another valve located ofdischarge of the extinguishing medium may adjacent the hazard to controlthe actual startinvolve from a few hundred pounds to several ing andstopping of the application of the extons per minute. The largest tankthus far intinguisher to the fire. To prevent liquid carbon stalled forconfining liquid carbon dioxide at a dioxide from being permanentlytrapped in the constant low temperature and pressure has a pipingbetween the respective valves of such a storage capacity of 125 tons andthe highest rate series, which trapping would result in the deofdischarge that has been found to be necessary velopment of a high vaporpressure in the pipfor a single hazard is six tons per minute. 00- ingdue to the absorption of heat by the liquid casionally a situation willbe encountered which carbon dioxide, all valves located upstream frommakes it necessary to locate the central supply the outermost one are ofa construction which tank several hundred feet from at least one willpermit trapped liquid carbon dioxide to flow hazard and, of course, apipe line must be ex back to the'source of supply whenever such uptendedfrom the tank to the hazard to carry the stream valves are subjected toapressure on their liquid carbon dioxide. Almost every system thatoutlet sides which exceeds the pressure on their provides protection forseveral independent hazinlet sides. ards requires the use of severalhundred feet of Still another object of the invention is to empip ng toproperly connect up all of the hazards ploy a series of flow controllingvalves which are with the carbon dioxide supply tank. adapted to beopened and closed by the con- It will be apparent from what has beenstated trolled application of differential fiuld pressures, above thatfire extinguishing systems of this type 40 and with the downstream valveor valves of the may very readily involve the handling of large seriesbeing so constructed that they will not be quantities of liquid carbondioxide under vapor caused to open prematurely or unintentionallypressures of several hundred pounds per square in response to the suddensurge or rush of fluid inch at rapid rates of discharge throughrelativethat is caused by the opening of the next adjaly largediametered pipes which extend a total cent upstream valve. of severalhundred feet. Handling conditions of Other objects and advantages of theinventhis character must necessarily present troubletion will beapparent during the course of the' some problems with reference to pipejoint and following description. valve leakage, strength of pipingrequired, trap- In the accompanying drawings forming a part ping ofportions of the extinguishingliquid in of this specification and inwhich like numerals certain sections of the piping after a discharge areemployed to designate like parts throughout at a given hazard or otheroperations of the systhe same, tern, etc. Figure 1 is a diagrammaticview of the type of It is the primary object of this invention to carbondioxide fire extinguishing system embodyprovide a form of fireextinguishing system which ing this invention,

Serial No. 467,191

may be constructed and installed at acomparatively low cost; which maybe adapted for handling either large or small quantities of liquidcarbon dioxide at any desired vapor pressure of this invention,

Figure 2 is a perspective view of a liquid carbon through the valvestructure of Figs. 3 and 4,

Figure 6 is a vertical sectional view of the master control valveemployed in the system of Fig. 1 and a pilot valve which is employed forcontrolling the application of difierential fluid pressures to themaster control valve to effect opening and closing operations 01' thelatter,

Figure '7 is an elevational view of the pilot valve of Fig. 6 with anelectric solenoid which is employed for operating the pilot valve,

Figure 8 is a sectional view taken on line 8-8 01' Fig. 7,

Figure 9 is a vertical sectional view of a selector valve employed inthe system 01' Fig. 1;

Figure 10 is a detail sectional view taken on line ill-l of Fig, 6,

Figure 11 is an elevational view of a modified form of pilot valve andits actuating mechanism which may be employed for controlling theapplication of operating fluid pressures to the master controlvalve andthe selector valves,

Figure 12is an end elevational view oi the mechanism shown in Fig. 11,and

Figure 13 is a detail sectional view taken on line l3-l3 of Fig. 11.

In the drawings, wherein for the purpose of illustration are shown thepreferred embodiments and first particularly referring to Fig. 1, thereare shown two different fire hazards which are to be given fireextinguishing system that embodies this invention. These hazards aredesignated by the reference characters A and B. As illustrated, theyconsist of enclosed spaces or rooms, but it is to be undertsood thatthis system is not limited in its use to the protection of this typeofhazard. The extinguishment of fires in enclosed spaces is thusaccomplished with carbon dioxide by totally flooding the spaces; i. e.,building up a concentration of carbon dioxide vapor which will notsupport combustion. By employing different types or sizes and differentarrangements of discharge devices, all types and kinds of hazards may befully and adequately protected by the illustrated system. It will benoted that hazard A is larger than hazard B. This type of illustrationis provided to show that the system is of such a flexible character thatit can be employed for eilectins extinguishment of diiferent sized firesand for protecting hazards which require different amounts of theextinguishing medium.

In the diagrammatic showing of Fig. l, the reference character I isemployed to designate the source of supply of liquid carbon dioxide.Because oi. the advantages to be obtained, it is preferred that'thissource of supply take the form of a single insulated tank in which theliquid carbon dioxide is stored and is maintained at a desired, constantsubatmospheric temperature and its corresponding low vapor pressure. Itis to be protection by the satisfactoiily if the liquid carbon dioxideis confined in either an uninsulated storage tank or proper capacity oruninsulated cylinders and with no means employed for maintaining theliquid at any constant, controlled temperature. It the liquid is to beobtained from a bank of cylinders, the usual practice of employingseparate discs and cutter devices for each cylinder should be dispensedwith and all of the cylinders should be placed in open communicationwith a manifold so that the flow of the carbon dioxide can be controlledby the valves of this system.

The source of supply of liquid carbon dioxide I! should be adequate toafiord the desired protection for the hazards A and B. The amount ofliquid carbon dioxide may be sufllcient for providing the followingtypes of discharges:

l. A single discharge that will effect extinguishment of fires in eachone of the two hazards A and B with no reserve for extinguishing a firein either hazard in case 01 a reflash.

2. A two shot discharge for either one 01 the two hazards which willeffect extinguishment 01 a fire and will extinguish any refiash that mayoccur.

3. A two shot" discharge for both of the hazards.

understood, however, that the system will operate Although thefllustration provided by Fig. 1 shows only two hazards being protected,it will be appreciated that any desired number of hazards may be takencare 01' by merely extending the illustrated system. It, also, should beunderstood that this type of system has been found to be very effectiveand eflicient in protecting a single hazard which must be located aconsiderable distance from the nearest place at which the source ofsupply may be positioned.

The liquid carbon dioxide is withdrawn from the source 01' supply I! bymeans of a dip-tube it that extends out of the storage tank, or thelike, for connection with the inlet side of the shutofl' valve IT. Theoutlet side of this valve i1 is connected by the pipe section It to theinlet side of the master control valve I9. When the system is in normaloperating condition, the shutofl' valve l1 stands open while the mastercontrol valve i9 is closed. The release or discharge of the carbondioxide from its source, therefore, is normally controlled by the mastervalve l9.

This master control valve i9 is intended to respond to the creation ofcertain fiuid pressure conditions within its housing. That is to say,the master control valve will be opened as a result of the creation ofone fluid pressure condition within its housing and it will be closed asa result of the creation of a different fluid pressure condition. Thesechanges in fluid pressures are accomplished by means 01 an electricallycontrolled pilot valve unit 20 that is connected to the pipe line i8 bythe tubing 2i and is connected to the master control valve housing bythe tubing 22. Circuit wires 23 and 24 extend from the electricalcontrol portion of the pilot valve unit 20 to the electric control box25.

With the master control valve I! normally closed, the remainder of thepiping of the system will not be subjected to the pressure of theliquidcarbon dioxide except when the system is placed in operation to effectextinguishment of a. fire in one or more of the hazards. Therefore,there is provided a non-pressure header 26 beyond the master controlvalve 18 which is connected to the various independent branch lines 21that extend to the different hazards. Each one 01' these theextinguishing medium from branch lines has connected therein a selectorvalve 28 which functions to controlthe fiow of the header 28 through abranch line 21 to the discharge device 28 which is properly associatedwith the hazard that is served by a given selector valve and its branchline. It will be noted that the discharge devices 28 are of differentsizes for the two hazards A and B. By employing different sizeddischarge devices, different amounts of carbon dioxide may be deliveredto the different sized hazards during a given discharge period. That isto say, different sized discharge devices 28 provide different rates ofrelease so that a smaller discharge device will effect delivery of asmaller amount of carbon dioxide during each minute of discharge than alarger device.

The selector valves 28 are intended to be conitrolled by the same typeof pilot valve and electric control unit as are used by the mastercontrol valve is and for that reason the same reference characters willbe applied. Circuit wires 38 and Si extend from the electrical portionof each pilot valve unit for each selector valve to the electric controlbox 28.

Although no attempt has been made to illustrate the feature in thediagrammatic showing of Fig. l, the header 28 and the portions of thebranch lines 21 that are arranged upstream with respect to the selectorvalves 28 should be inclined or otherwise suitably arranged so that anyliquid carbon dioxide that may be trapped between the master controlvalve l8 and the selector valves 28 may drain back to the source ofsupply l5. The short pipe section l8 and the dip-tube 16, also, shouldbe arranged so as to permit the return of liquid to the source of supply15. Gravitational flow of this liquid is all that is ordinarily requiredto effect this return movement of the liquid. When the detail featuresof construction of the shut-off valve l1 andmaster control valve l8 areexplained in connection with otherfigures .of the drawings, it will beshown how this liquid carbon dioxide will be permitted to return to thesource of supply. It will be explained at this time, however, that thisreturn of trapped liquid results from the building up of a predeterminedvapor pressure within theportions of the piping located between thevalves that create the trapped conditions. This building up of vaporpressure results from the absorption of heat by the trapped liquid andthe vaporization of a portion of the liquid. The greater the amount ofheat absorbed by the liquid, the greater the amount of liquid that isvaporized. The liquid naturally will occupy the lower portion of thepiping in which it is trapped while a vapor space will be formed in theupper portion of the piping. A vapor operated whistle 32 is connected tothe header 28 at a suitable high point which will receive the carbon(11-. oxide vapor. This whistle may be of any suitable construction,such as a centrally apertured wafer or peanut venders whistle, whichwill be operated as carbon dioxide vapor is slowly bled therethrough.This whistle will function to indicate to an attendant that liquidcarbon dioxide is trapped in the header 28. It, also, will function tobleed off all of the vapors that remain after the liquid has beenreturned to the source of supply IS. It will be apparent, therefore,that the header 28 will again be returned to its non-pressure condition.

The two hazards A and B are each provided with a suitable number ofcircuit closing, fire detecting devices 33. The fire detecting devicesfor each hazard are connected in parallel with the circuit wires 38 and35 which extend to the electric control box 25. It will be understoodthat each one of these fire detecting devices 33 will be capable ofclosing the circuit between its two wires 3| and 35 when said device issubjected to a certain degree of temperature, or a certain rateof-riseof temperature as a result of the presence of a fire in the hazard thatis protected by the detecting device. Each one of the two fire detectingcircuits may be closed by a manual switch 38 which may be located at anydesired point relative to its hazard.

Electricity is supplied to the control box 25 by means of the two powerlines 31 and 38, the double-pole, single-throw switch 39 and the wires40 and 4!.

The operation of the system diagrammatically illustrated in Fig. 1 nowwill be explained. Whenever a fire occurs in either one ofthe twohazards protected by the system, its existence will be detected by oneof the devices 33 and this device will operate to close the circuitthrough its wires 34 and 35. If the existence of a fire is observed bysome person before one of the automatic detecting devices 33 isoperated, the circuit through the wires 34 and 35 may be closed by theappropriate manually operable switch 38. The closing of one of thedetector circuits will start in motion the electric control mechanismconfined in the control box 25. This mechanism will operate to firstclose the circuit to the electric portion'of the pilot valve unit 28 forthe master control valve I9 through the wires 23 and 24. A circuit willalso be closed to the electrical portion of the pilot valve unit 20which is associated with the selector valve that controls the deliveryof carbon dioxide to the particular hazard that is involved. The closingof the circuits to the two pilot valve units 20 will create fluidpressure conditions in the housing of the master control valve l9 andthe housing of the proper selector valve 28 for causing these two valvesto open. The liquid carbon dioxide will then flow from the source ofsupply l5 through thedip-tube IS, the short pipe line l8, the header 2Gand the proper branch line 21 to the discharge device 29 and will bereleased by this discharge device into the proper hazard.

By employing a time cycle controller of the type disclosed in the patentto Joseph H. Staley, No. 2,141,024, in the electric control box 25 fortiming the opening and closing operations of the circuits 2324 and3ll--3l -to the pilot valve units of the master control valve l9 and theproper selector valve 28, the lenth of time these valves stand open maybe controlled. As the rate of discharge of carbon dioxide to a hazardmay be controlled by the capacity of its discharge device 28, or by thefiow capacity of the branch line 21 and/or the selector valve 28, apredetermined amount of carbon dioxide will be delivered to a particularhazard whilethe master control valve and the selector valve stand open.After the elapse of the proper discharge period, the master controlvalve andthe actuated selector valve will be closed automatically. Thiscontrol and two additional discharges for the second hazard.

After the master control valve I 9 and the actuated selector valve 28are closed, liquid carbon dioxide will be trapped in the header 26 andboth of the branch lines 21 up to the selector valves 28. As pressuredevelops in the piping by the absorption of heat by the trapped liquid,the master control valve l9 will open to permit the liquid to drain backinto the source of supply I5. The whistle 32 will function to servenotice that liquid carbon dioxide is trapped in the header and it willalso function to vent the carbon dioxide vapor that remains after theliquid is drained back into the source of supply.

The shut-off valve I1 is normally locked open. However, this valve maybe manually closed whenever it is necessary to test, adjust or repairany of the piping or the control instrumentalities of the system. If theclosing of this shut-off valve results in trapping liquid in the pipesection I8, the shut-off valve I! will function to permit this trappedliquid to drain back into the source of supply l so that an excessivepressure will not develop in the pipe l8.

It was explained above that the source of supply of liquid carbondioxide I5 preferably should take the form of a single, insulatedstorage tank in which the liquid carbon dioxide was maintained at apredetermined, constant, subatmospheric temperature, and itscorresponding low vapor pressure, by means of a suitable refrigeratingdevice although the source of supply might take the form of a bank ofhigh pressure cylinders. Fig. 2 discloses the preferred type of supplyunit. It includes a tank 42 which is surrounded by suitable insulatingmaterial and is confined within a suitable housing 43. The end portion43a of this housing forms a chamber in which is located a suitablemechanical refrigerator unit of conventional design. No attempt has beenmade to disclose such a unit but it is provided with a condenser coil 44which is located in the vapor space of the tank 42 and functions tocondense the carbon dioxide vapor and cause it to drop into the body ofliquid confined in the liquid space of the tank. The mechanicalrefrigerator unit is ventilated by suitable grill panels 45 which arelocated in opposite side walls of the end compartment 43a.

A suitable instrument panel 46 is mounted in the end wall 41 of thehousing and includes a liquid level gage 48, a pressure gage 49 and apressure control switch 50. The liquid level gage 48 functions toindicate the amount of liquid present in the tank 42. The pressure gage49 functions to give a visible indication of the pressure that prevailswithin the tank 42. The pressure control switch 50 operates in responseto pressure changes within the tank 42 to control the operating periodsof the mechanical refrigerating device located in the end compartment43a.

When the supply of liquid carbon dioxide for the tank 42 is to bereplenished, a transportation truck or railway tank car is employed forcarrying the low temperature and pressure liquid carbon dioxide to thelocation of the storage unit l5. The liquid space of the transport unitis connected to the bottom of the tank 42 by means of the pipe 5| whilethe vapor space of the transport unit is connected to the upper portionof the storage tank 42 by means of the vapor pipe 52. These twoconnections will function to equalize the vapor pressures existing inthe transport tank and the storage tank. It willbe noted that the vaporline 52 extends a certain distance into the tank 42. This vapor lineshould extend about one-seventh of the internal diameter of the tank 42and thereby function to prevent the tank from being filled with liquidbeyond six-sevenths of its depth.

A pipe 53 is connected to the top of the tank 42 and extends outside ofthe housing 43 for connection with the safety head assembly 54. Thisassembly includes two direct spring-loaded pop valves 55 which are setto open and bleed oil carbon dioxide vapor whenever the pressure in thetank 42 rises to a certain value above the desired maximum pressure thatis intended to be maintained by the mechanical refrigerator unit. Inother words, should the mechanical refrigerator unit fail to operate tohold the vapor pressure within the tank 42 at the desired workingpressure and the pressure is caused to rise to the operating pressure ofthe valves 55, due to the input of heat through the tank insulation,these valves will open to vent carbon dioxide vapor. This release ofvapor from the tank will cause a proper amount of the liquid to vaporizeand thereby bring about a self-cooling or refrigerating action whichwill lower the temperature of the remaining liquid. The safety headassembly 54 also includes a frangible or rupturable disc unit 56 whichwill blow out at a predetermined pressure that is above the operatingpressure of the relief valves 55 but below the maximum pressure at whichthe tank 42 has been tested to determine its maximum safety pressure.

The tank shut-oil valve I! will be described in detail in connectionwith the disclosures of Figs. 3 to 5 inclusive. This is a manuallyoperable gate valve which includes the body 51 that is suitablythreadedly connected at its inlet side 58 to the upper end of thedip-tube I6. A nut 59 is threaded in the opening 60 of the body 51 andprovides a coupling for connecting the discharge side of the valve tothe pipe section It that extends to the master control valve. This nut59 also functions to provide a seat 6| for the valve disc 62 to engage.This valve disc 62 is attached to the disc carrier 63 by the telescopicjoint 64 which permits the valve disc to partake of axial movementrelative to the carrier 63. A compression spring 65 is interposedbevalve disc in the direction of flow 01 fluid through the valve body.An opening 66 is also formed in the portion of the valve disc carrier 63which overlies the rear or upstream side of the valve disc. This openingfunctions to admit the liquid carbon dioxide to the rear face of thevalve disc 62 so that the pressure of the liquid will cooperate with theload provided by the spring 65 for retaining the valve disc 82 in tightengagement with its seat 6|.

A rotatable stem 61. extends through a bushing assembly 68 that ismounted in one side wall of the housing 57. This stem is suitablyattached to the valve disc carrier 63 so that rotation of the stem willcause the carrier to be moved to either seat or unseat the valve disc62, depending upon the direction of rotation of the stem 61.

The outer end of the stem 61 has suitably splined or keyed thereon theworm wheel sector 89 which meshes with the worm gear 10 that is carriedby the worm shaft 1| joumaled in the mounting or bracket 12 carried bythe valve housing 51. The worm shaft 1| is illustrated in Figs. 3 and 4as having a hand wheel 13 mounted on one end thereof. Manual operationof this wheel will accomplish opening and closing movements of the valvedisc 82.

The worm wheel sector 69 has the words "open" and closed' suitablyapplied thereto. These words are intended to cooperate with the fixed Ipointer I4 for indicating the positions of the valve disc 92. The wormwheel sector 69 also is provided with an apertured keeper I 5 whichcooperates with a similar keeper I8 that is suitably attached to theworm shaft supporting bracket or mount I2. The apertures of these twokeepers. I5 and 18 will register when the pointer 14 registers with theword "open so that a padlock may be used to hold the worm wheel sector88 in this position. This locking mechanism functions to preventunauthorized closing of this shut-off valve I1.

Fig. 5 shows the valve disc 82 in engagement with its seat 8|. As thistank shut-off valve is normally open, carbon dioxide is normally presentin the dip-tube I6 and the pipe section I8. The master control valve I9,see Figs. 1 and 2, is normally closed for preventing the carbon dioxidefrom flowing into the header 26. Therefore, whenever the shut-off valveI1 is closed, carbon dioxide will be trapped in the pipe section I8. Asthis trapped carbon dioxide is isolated from the carbon dioxide in thetank 42, its temperature and pressure conditions will not be controlledby the mechanical refrigerator unit that is connected to the tank andthe input of heat through the wall of the pipe I8 will cause thepressure of this trapped carbon dioxide to rise. When th pressure ofthis trapped carbon dioxide exceeds the pressure applied to the rearface of the valve disc 62; i. e., the pressure developed by the carbondioxide in the dip-tube I6 and the valve disc loading spring 65, thevalve disc 82 will be unseated and thereby balance the pressure in thedip-tube I6 and the pipe I8. It will be appreciated, therefore, thatthis yieldably seated valve disc 82 will permit liquid carbon dioxide tobe returned to the tank 42 and will function to prevent the building upof an excess pressure in the pipe section I8.

The master control valve is disclosed in detail in Figs. 6 and 10. Thevalve casing I1 is of hollow construction to provide an inlet pressurechamber is with a power cylinder 19 overlying the chamber and in fullyopen communication therewith. The inlet side of the casing 11 issuitably constructed at 80 to be connected with the pipe section I8 inthe manner illustrated. The outlet side of the valve casing I1 isprovided with an opening 8I adapted to receive the member 82 that isshaped to provide a valve seat 83. This member 82 is flanged at. 84 toaccommodate the threaded securing studs 85 by means of which the member82 is secured to the valve casing TI.

tion of this extension will be explained at a later point. The coverplate is recessed or pocketed at 8| to receive. the upper end portion ofthe coil spring 92 when the spring is expanded. This recess or pocket 9|also functions as a part of a nesting space for the spring when thelatter is compressed as a result of opening operation of the valve. Therecess or pocket 9| is tapped at 93 to receive the coupling sleeve 94 bymeans of which the tube 22 is connected to the valve casing I1.

This member 82 functions as a coupling be- I tween the valve casing 11and the pipe header 26 by being thieadedly connected at 89 to saidheader. A gasket 81 is provided to prevent leakage between the valvecasing I1 and the header The upper open end of the power cylinder I9 isadapted to be closed by the flanged cover plate 88 which is secured inplace by the studs or screws 89. A packing gasket 90 is interposedbetween the cover plate 88 and the upper end of the valve casing toprevent leakage between these two mem bers. It will be noted that thisgasket 90 extends inwardly of the power cylinder wall. The func- Thismaster control valve is provided with a valve disc that has the seatingwasher 99 se cured thereto by means of the retainer 81. This seatingwasher 96 is formed of any suitable material, such as a synthetic rubberthat will withstand low temperatures. A valve disc carrier 98. whichtakes the form of a bell crank lever} is pivotally connected to the backof the valve disc 95 by means of the pin 99 which passes through theapertured ears I00 that are formed on the back of the disc. The endportion of the carrier 98 which is pivotally connected to the valve disc96 is provided with shoulders IOI which are spaced a suitable distancefrom the rear face of the valve disc 95 to allow for a limited amount ofpivotal movement between th valve disc and its carrier 98. Thisclearance allows for just sufficient action of the valve disc to assurean even distribution of pressure on the valve seat 93 by the top andbottom portions of the disc. This slight pivotal movement of the valvedisc relative to its carrier also provides uniform seating in case thevalve disc washer 96 becomes permanently compressed.

The remaining end of the bell crank lever type of disc carrier 99 ispivotally connected to the valve casing 11 by means of the hinge pinI02. This type of carrier mounting for the valve disc will permit thevalve disc and its seating washer to swing open against the direction offlow of fluid through the valve casing and into a position where thevalve assembly will not obstruct the path of flow of the fluid. In otherwords, the valve, when fully opened,will provide a straightthrough flowfor the fluid which will not be obstructed by the valve and will notprovide any appreciable pressure drop.

A power piston I03 is positioned in the power cylinder 19 and isprovided with a bifurcated piston rod I04 that i pivotally connected tothe intermediate or elbow portion of the bell crank lever valve disccarrier 98 by means of the piston pin I05. The power piston I03 issubstantially cup-shaped to provide the pocket or recess I06 forreceiving the lower end portion of the spring 92. This pocket or recessI06 cooperates with the pocket or recess 9| of the cover plate 88 forcompletin the nesting space for the coil spring 92' when the powerpiston I03 is moved upwardly as far as possible. The power piston bodyis provided with a top flange I01 which is tapered or beveled at itsperiphery I08 to permit the power piston to partake of a tilting motionwhen the piston moves through the power cylinder. This tilting motionprevents binding of the piston in the cylinder and is made necessary bythe fact that no lost motion or play is allowed between the piston pinI05 and either the bifurcated piston rod I04 or the valve disc carrier98.

Figs. 6 and 10 disclose a cup-leather I09 for packing between the powerpiston I03 and the wall of the power cylinder 19. This cup-leather I09constitutes the main bearing for the power steel strips and thecup-leather I09 are clamped against the bottom face of the flange I01 ofthe power piston by the retaining ring III which is threadedly mountedon the periphery of the cupped body portion of the power piston I03.

It was explained in connection with the disclosure of Fig. 1 that apilot valve unit 20 was employed for creating suitable pressureconditions within the valve casing 11 to accomplish opening and closingoperations of the valve. This pilot valve unit controls the flow ofcarbon dioxide from the pipe section I8 through the tubes 2| and 22 intothe power cylinder I9. That is to say, when the pilot valve is in itsnormal condition of operation the tubes 2I and 22 will be placed incommunication with each other and carbon dioxide will flow from the pipeI8 into the power cylinder I9. The pilot valve unit 20, however, iscapable of being conditioned so that flow of carbon dioxide through thetube 2| will be stopped and the power cylinder I9 will be placed incommunication with the atmosphere, or the carbon dioxide pressuredeveloped in the cylinder I9 will be vented to the atmosphere to reducethe pressure in this power cylinder below the pressure prevailing in thepipe section I 8 and the inlet pressure chamber I8.

Let us now consider that no fluid is present in the pipe section l8 orin any portion of the valve casing. When this condition exists, thevalve disc will be seated and retained in that position solely by theload imposed on the power piston I03 by the spring 92. Let us nowconsider that carbon dioxide is admitted to the pipe I8 and that thepilot valve unit 20 is in its normal or open position so that the tubes2| and 22 are placed in communication with each other. When thiscondition prevails, the same fluid pressure is developed in the inletpressure chamber I8 and the power cylinder 19 so that the same pressureis applied to both faces of the power piston I03. As the fluid pressureson the opposite sides of the power piston are equalized, the valve disc95 will be held closed or in its seated position by the pressure of thespring 02 and by the application of fluid pressure to the back orupstream surface of the disc 05.

When it is desired to cause the valve to open,

the pilot valve unit 20 is actuated to close the tube 2I and to vent thetube 22 to the atmosphere. This venting of the tube 22 also vents thepower cylinder I8 so that atmospheric pressure prevails in thiscylinder. The fluid pressure of the carbon dioxide in the inlet pressurechamber I8 will then be applied to the inner face of the power pistonI03 and, of course, still to the upstream face of the valve disc 95. Thefluid pressure applied to the inner face of the power piston I 03,therefore, opposes the load provided by the spring 92 and the fluidpressure applied to the back or upstream face of the valve disc 95. Thearea of the inner face of the power piston relative to the area of theupstream face of the valve disc 95 is such that substantially atwo-to-one pressure ratio is provided in favor of the power piston. Thisdifferential fluid pressure in favor of the power piston will cause thelatter to move upwardly through the power cylinder I9 to efiect openingmovement of the valve disc 95. This upward movement of the power pistonis limited by sealing engagement of its flange I01 with the inwardlyprojecting portion of the packing gasket 90. This sealing engagement ofthe power piston with the packing gasket supplements the sealing actionaccomplished by the cup-leather I00, while atmospheric pressure prevailsin the power cylinder I0, to prevent any leakage of carbon dioxide intothe space formed by the spring receiving pockets or recesses 9| and I08.If liquid carbon dioxide were permitted to pass into this.

vented space, the resulting pressure drop would cause the liquid toflash to a mixture of carbon dioxide snow and vapor. The snow would belikely to plug up or close the passage through the coupling 94 and thetube 22 and cause pressure to build up above the power piston whichwould bring about a premature closing of the valve.

When it is desired to again close or seat the valve disc 95, the pilotvalve unit 20 is operated to prevent venting of the tube 22 to theatmosphere and to again connect the tube 2| with the tube 22. Pressurewill then be built up in the power cylinder I8 until the pressure inthis cylinder equalizes the pressure in the inlet chamber 18. The spring92 and the fluid pressure applied to the valve disc 95 will then causethe valve disc to be closed or seated.

The drawings disclose two different types of pilot valve units 20 forcontrolling communication between the tubes 2| and 22. One form of unitis disclosed in Figs. 6 to 8 inclusive. The other form is disclosed inFigs. 11 to 13 inclusive. The principal difference between these twotypes of units is that the form shown in Figs. 6 to 8 inclusive isdependent entirely upon the opening and closing of an electric circuitfor a solenoid to effect actuation of the pilot valve per se while theform shown in Figs. 11 to 13 can be operated manually in addition tobeing electrically operated. The form of pilot valve unit shown in Figs.6 to 8 inclusive will first be described in detail. Fig. 6 shows a pilotvalve body I I2 which is of hollow construction to provide the valvechamber I I 3. A valve plunger H4 is positioned in this chamber and hasthe spring II5 bearing thereagainst to normally cause the plunger toengage the seat I I 6. This seating engagement closes oil the passage II1 which functions to vent the pilot valve chamber H3 to the atmosphere.A second valve seat H8 is provided at the opposite end of the chamberH3. This second valve seat surrounds the passag H9 through the couplingnut I2 0 that is threaded in one end of the pilot valve casing andfunctions to connect the end of the tube H to the pivot valve casing.The tube 22 communicates with the pilot valve casing chamber II3 throughthe tapped opening I 2|. A plunger stem I22 extends from the pilot valvecasing and is intended to be operated by suitable mechanism so that whenthis mechanism is actuated, the valve plunger II4 will be moved from thposition illustrated in Fig. 6, where it engages the seat Hi, to aposition where it will engage the seat H8. The position of the plungerII4 illustrated in Fig. 6 is such that the tubes 2I and 22 will beplaced in communication with each other. When the plunger I is movedinto engagement with the seat H0, the tube 2| will be closed and thetube 22 will be vented to the atmosphere through the passage 1.

Figs. 7 and 8 disclose in detail the electric operating mechanism forthe pilot valve II 2. This mechanism includes a mounting plate I 23v.asnsaaeo 7 to which the pilot valve H2 is suitably connected. Asolenoid I24 also is connected to this mounting plate. This solenoidincludes a suitable casing I25 in which is mounted the electric coilI28. An armature I21 is mounted in the bore of th coil and is providedwith an operating rod I28 that passes through the mounting plate I23.The outer end of this operating rod loosely passes through one end of avalve operating lever I29. A shock absorbing spring I30 is interposedbetween the outer face of the lever I29 and an a'djustable nut I3I whichis'threaded on the end of the rod I28. The remaining end of the lever isfulcrumed on a mounting pin I32 so that the lever will pivot when thesolenoid armature I21 moves inwardly and outwardly relative to its coilI28. Fig. '1 clearly illustrates the lever as overlying and engaging theouter end of the plunger rod I22. It will be apparent, therefore, thatwhen the solenoid coil I28 is energized to cause the armature I21 tomove inwardly, the valve operating lever I29 will be pivoted relative toits fulcrum pin I32 and this pivotal movement of the lever I29 willcause the pilot valve plunger operating rod I22 to move inwardly. Thisinward movement of the plunger rod will continue until the plunger bodyH4 is moved into engagement with the seat II8, see Fig. 6. If thisengagement of the plunger II4 with its seat H8 occurs before thesolenoid armature I21 reaches its inner limit of movement, th springconnection I30 between the armature rod I20 and the lever I29 willpermit the armature to continue its movement without damaging the pilotvalve plunger II4.

The form of pilot valve unit shown in Figs. 11 to 13 includes the samepilot valve II2 withits tubes 2I and 22, its vent port or passage H1,and the pilot valve plunger operating rod I22. This pilot valve isconnected to a mounting plate I32. This mounting plate also has securedthereto an electric solenoid I33 that has an armature operated rod I34projecting through the mounting plate I32. This rod isbifurcated at itslower end I34a to allow for the passage of one end of the valveoperating lever I35 which is pivotally mounted at its other end-by thepin I38 that is carried by the mounting block I31. A shock absorbingspring I38 encircles the outer end portion of the armature operated rodI34 and engages a stop pin I39. This spring engages the valve operatinglever I35 in the manner clearly illustrated in Figs. 11 and 12. Thelever I35 is provided with an adjustable screw. I40 which has its headarranged to engage the outer end of the pilot valve plunger operatingrod I22.

The mechanism so far described functions in the same manner as themechanism specifically plate I51.

described in connection with Figs. 7 and 8. The

unit of Figs. 11 to 13 inclusive, however, has added thereto a crankshaft I4I that is mounted for angular movement in the arms of the U-shaped bracket I42. This crank shaft MI is adapted to be operated by thehand wheel I43. The inner end of this shaft has a crank or throw I44that passes through the hooked end I45 of the rod I48. This rod passesthrough the mounting plate I32 and the lever I35. A shock absorbingspring I41 is mounted on the end of the rod I48 and is held in place byth adjustable nut I48.

It will be appreciated that angular movement of the crank shaft MI ineither direction will cause the rod I48 to be pulled upwardly forrocking thelever I35 in the same manner as the lever is actuated by thesolenoid armature rod I34. This pilot valve unit I20 of Figs. 11 to 18inclusive, therefore, can be automatically operated by the solenoid I33or manually operated by 5:16 hand wheel 3' and its associated elemen s.

The selector valves 28, shown in Fig. 1, are

of identical construction and one of them is shown in detail in Fig. 9.The construction of this selector valve is very similar to theconstruction of the master. control valve shown in Fig. 6. The selectorvalve, however, differs in one important way from the construction ofthe master valve.

It will be appreciated that the master control valve normally is closedand prevents the. application of fluid pressure to the selector valves.However, when the master control valve is opened a sudden surge or rushof fluid pressure will be applied to the inlet side of each selectorvalve. As this sudden rush of pressure can build up more quickly in theinlet pressure chamber I48 of the selector valve casing I50 than it canin the power cylinder I5I, due to the restricted ilow path provided bythe tubes 2I and 22 and the pilot valve II2, the lower face of the powerpiston I52 will be subjected to a higher pressure than th upper face ofthis piston and the selector valve would be caused to open eitherprematurely or unintentionally. The selector valves, therefore, must beconstructed so that this sudden surge or rush of fluid will not causethem to be opened.

The selector valve casing I50 is flanged at its inlet end I53 and at itsoutlet end I54 for connection with the sections of the branch line 21.The outlet for the pressure chamber I49 is provided with a seat I55.This seat cooperates with the valve disc and carrier structure which areidentical with the elements disclosed and described in connection withthe master control valve of Fig. 6. Therefore, the same referencecharacters will be applied to these elements.

The valve casing I50 is provided with a top opening I58 that ispartially closed by the barrier This plate is formed with a centralopening I58 and a suitable packing structure I59 is provided to preventleakage between this barrier plate I51 and the valve casing. A seatingring I is recessed in the upper surface of the barrier plate I51.concentrically with the opening I58 and so as to be exposed at the lowerend of the power cylinder I5 I This power cylinder is formed by asection of steel tubing I8I. The opposite ends of this cylinder tubingare seated in packed recesses I82 and I83 formed respectively in theupper surface of the barrier plate I51 and the inner surface of theflanged cover plate I84. The barrier plate I51, power cylinder tube I8Iand cover plate I84 are maintained in proper assembled relation by thebolts I85.

The cover plate is recessed or pocketed at I88 to accommodate the upperend. portion of the power piston loading spring I81. This pocketedportion of the cover plate is provided with a tapped opening I88 toreceive the coupling I89 which is employed for connecting the tube 22that leads from the pilot valve II2, not shown in this figure.

The power piston I52 is provided with a bifur-' end portion. of theloading spring I81. This power piston is provided with a top flange I12that is peripherally tapered or beveled at I13 to allow for tiltingmovement of the piston when it reciprocates through the power cylinderI6I. A packing cup-leather I14 is provided for the power piston I 52 anda series of reinforcing spring steel strips I15 is provided for thecup-leather in the same manner as the power piston of the master controlvalve. A retainingring I16 is provided to clamp the cup-leather I14 andthe spring strips I15 against the lower face of the flange I12.

This-power piston is provided with an annular seating rib or projectionI11 which'is intended to seat against the ring I60 when the power pistonis in its lowermost position, or the position it assumes when the valvedisc 95 is closed. A relatively small bleeder port or opening I18 isformed in the power piston I52 to provide a restricted flow path orpoint of communication between the inlet chamber I49 of the valve casingand the annular space that surrounds the body of the power piston and isdefined at its opposite ends by the barrier plate I51 and the pistonflange I12 with its packing assembly.

The mode of operation of this valve now will be described.

With no fluid pressure within the inlet chamber I49 of the valve casingI and the power cylinder I5I, the spring I61 will retain the valve disc95 in its seated position. The power piston I52 also will have itsseating ring or projection I11 in engagement with the seating washer Icarried by the barrier plate. When this valve structure is subjected toa sudden surge or rush of fluid, the fluid flows into the inlet chamberI49 and is quickly applied to the inner or rear surface of the valvedisc 95 and the portion of the lower surface of the power piston whichis surrounded by the annular seating ring or projection I11. Fluidpressure also builds up in the power cylinder I 5| as a result of flowof the fluid through the tubing 2| and 22 and thegpilot valve IZI. Thesmall bleeder port or opening I18 formed in the power piston I52 alsopermits fluid pressure to build up in the annular space that surroundsthe periphery of the power cylinder. This building up of fluid pressurein the annular space, however, is at a slower rate than the rate ofdevelopment of fluid pressure within the power cylinder I5I. Therefore,a superior fluid pressure will first be created within the powercylinder I5I. This fluid pressure applied to the upper surface of thepower piston will first exceed the total value of the fluid pressureapplied to the lower surface of the power piston and these opposed fluidpressures will become equal when the pressure developed in the annularspace surrounding the power piston equals the pressure developed in thepower cylinder I5 I. The sudden surge or build up of fluid pressurewithin the valve casing inlet chamber I49, therefore, will not cause thevalve disc 95 to be opened. This selector valve will only be opened inits normal intended manner; i. e., by venting of the power cylinder I5Iby means of the pilot valve I I2.

It is to be understood that the forms of this invention herewith shownand described are to be taken as preferred examples of the same, andthat various changes in the shape, size, and arrangement of parts may beresorted to without departing from the spirit of the invention or thescope of the subjoined claims.

Having thus described the invention, I claim:

. l. A fire extinguishing system for protecting one or more separatehazards, comprising a source of supply of liquid carbon dioxide, pipingexcarbon dioxide at the hazard served thereby, said master valveincluding a seating member, and means for applying a yieldable load tosaid member to hold it against its seat so that a rise in vapor pressureof liquid carbon dioxide, trapped in the piping downstream of the mastervalve, to a value sufilcient to overcome the load applied to the seatingmember will effect unseating of said member to cause trapped liquidcarbon dioxide to be returned to the source of supply.

2. A flre extinguishing system for protecting one or more separatehazards, comprising a source of supply of liquid carbon dioxide, pipingextending from said source of supply to the one or more separate hazardsto be protected and including ,a branch line for each hazard and aheader common toall of the branch lines, a master valve adjacent thesource of supply for the source of supply to prevent flow of carbondioxide from said source when closed, and a setnereby, said shut-01fvalve including a seating member, and means for applying a yieldableload o said member to hold it against its seat so that a rise in vaporpressure of liquid carbon dioxide,

trapped in the piping downstream of the shut-oil valve, to a valuesuflicient to overpower the load applied to the seating member willeffect unseating of said member to cause trapped liquid carbon dioxideto be returned to the source of supply.

3. A fire extinguishing system for protecting one or more separatehazards, comprising a source of supply of liquid carbon dioxide, pipingextending from said source of supply to the one or more separate hazardsto be protected and including a branch line for each hazard and a headercommon to all of the branch lines and draining toward said source ofsupply, a master valve adjacent the source of supply for controlsupply.

4. A flre extinguishingsystem for protecting one or more separatehazards, comprising a source or supply or liquid carbon dioxide,.pipingextending from said source or supply to the one or more separate hazardsto be protected and including a branch line for each hazard and a headercommon to all of the branch lines, a master valve adjacent the source ofsupply for controlling the flow of carbon dioxide through the header tothe branch lines, and a selector valve in-each branch line forcontrolling discharge of carbon dioxide to thehazard served thereby,said master valve including a seating member closing in the direction offlow of the carbon dioxide through the valve, and means for applying ayieldable load to said member to hold it against its seat-so that a risein the vapor pressure of liquid carbon dioxide, trapped in the pipingdownstream of the master valve, to a value sufiicient to overpower theload applied to the seating member will effect unseatin of said memberto cause trapped liquid carbon dioxide to be returned to the source ofsupply. v

5. A fire extinguishing system for protecting one or more separatehazards, comprising a source of supply of liquid carbon dioxide, pipingextending from said source of supply to the one or more separate hazardsto be protected and including a branch line for each hazard and a headercommon to all of the branch lines, a master valve adjacent the source ofsupply for controlling the iiow of carbon dioxide through the header tothe branch lines, a selector valve in each branch line for controllingthe discharge of carbon dioxide at the hazard served thereby,

and an electric control system operating in response to the detection ofa fire at a hazard for eilecting opening and closing of the master valveand the selector valve for the involved hazard, said master valveincluding a. seating member, and means for applying a yieldable load tosaid member to hold it against its seat so that a rise in the vaporpressure of liquid carbon dioxide, trapped in the piping downstream ofthe master valve, to a value suflicient to overpower the load applied tothe seating member will effect unseating of said member to cause trappedliquid carbon dioxide to be returned to the source of supply.

6. A fire extinguishing system for protecting one or more separatehazards, comprising an insulated storage tank for liquid carbon dioxide,means for maintaining the liquid carbon dioxide at a constant lowtemperature and its corresponding low vapor pressure, piping extendingfrom said tank to the one or more separate hazards to be protected andincluding a branch line for each hazard and a header common to all ofthe branch lines, a master valve adjacent the tank for controlling theflow of carbon dioxide through the header to the branch lines, and aselector valve in each branch line for controlling discharge of carbondioxide at the hazard served thereby, said master valve including aseating member, and means for applying a yieldable load to said memberto hold it against its seat so that a rise in the vapor pressure ofliquid carbon dioxide, trapped in the piping downstream of the mastervalve, to a value suiilcient to overpower the load applied to theseating member will efiect unseating oi said member to cause trappedliquid carbon dioxide to be returned to thetank.

7. A fire extinguishing system for protecting one or more separatehazards, comprising an insulated storage tank for liquid carbon dioxide,means for maintaining the liquid carbon dioxide sponding low vaporpressure, piping extending from said tank to the one or more separatehazards to be protected and including a branch line for each hazard anda header common to all of the branch lines and draining toward saidtank, a master valve adjacent the tank for controlling the ilow ofcarbon dioxide through the headerto the branch lines, a selector valvein each branch line for controlling discharge of carbon dioxide at thehazard served thereby, said master valve including a seating member, andmeans for applying a yieldable load to said member to hold it againstits seat so that a rise in the vapor pressure of liquid carbon dioxide,

at a constant low temperature and its corretrapped in the pipingdownstream of the master valve, to a value suflicient to overpower theload applied to the seating member will eflect unseating of said memberto cause trapped liquid carbon dioxide to be returned to the tank; and avapor operated signal device connected to a high portion of the headerand operable to indicate ,the presence of carbon dioxide trapped in theheader and to slowly bleed vapor from the header. 8. A fireextinguishing system for protecting one or more separate hazards,comprising an insulated storage tank for liquid carbon dioxide, meansfor maintaining the liquid carbon dioxide at a constant low temperatureand its corresponding low vapor pressure, piping extending from saidtank to the one or more separate hazards to be protected and including abranch line for each hazard and a header common to all of the branchlines, a master valve adjacent the tank for controlling the flow ofcarbon dioxide through the header to the branch lines, a selector valvein each branch line for controlling dis-- charge of carbon dioxide atthe hazard served thereby, and an electric control system operating inresponse to the detection of a fire at a hazard for effecting openingand closing of the master valve and the selector valve for the involvedhazard, said master valve including a seating member, and means forapplying a yieldable load to said member to hold it against its seat sothat a rise in the vapor pressure of liquid carbon dioxide, trapped inthe piping downstream of the master valve, to a value sufilcient tooverpower the load applied to the seating member will effect unseatingof said member to cause trapped liquid carbon dioxide to be returned tothe tank. 9. A fire extinguishing system. for protecting one or moreseparate hazards, comprising a source of supply of liquid carbondioxide, piping extending from said source of supply to one or moreseparate hazards to be protected and including a branch line for eachhazard and a header common to all of the branch lines, a master valveadjacent the source of supply for controlling the flow of carbon dioxidethrough the header to the branch lines and a selector valve in eacnbranch line for controlling discharge of carbon dioxide at the hazardserved thereby, said master and selector valves each including a seatingvalve disc, a fluid operated power piston connected to the valve discfor moving the same between its open and closed positions, a powercylinder receiving the power piston and in open communication at itsinner end with the inlet of the valve so as to subject one face of thepower piston to the fluid pressure developed in said inlet, apilot lineconnecting the outer end of the power cylinder with the piping upstreamof the valve, and a pilot valve in the pilot line having means fornormally eflectlng flow oi fluid into the outer end of the powercylinder to cause the valve disc to be seated but being operable toeffect venting of the outer end of the power cylinder to the atmosphereto cause the valve disc to be unseated.

10. A fire extinguishing system for protecting one or more separatehazards, comprising a source of supply of liquid carbon dioxide, pipingextending from said source of supply to the one or more separate hazardsto beprotected and including a branch line for each hazard and a headercommon to all of 'the branch lines, a master valve adjacent the sourceof supply for controlling the flow of carbon dioxide through the headerto the branch lines, and a selector valve in each branch line forcontrolling discharge of carbon dioxide at the hazard served thereby,said master and selector valves each including a seating valve disc, afluid operated power piston connected to the valve disc for moving thesame between its open and closed positions, a power cylinder receivingthe power piston and inopen communication at its inner end with theinlet of the valve so as to subject one face of the power piston to thefluid pressure developed in said inlet, and controllable means forselectively creating equalized or differential fluid pressures in theinlet of the valve and in the power cylinder outwardly of the powerpiston to cause the valve disc to be seated or unseated respectively.

11. A fire extinguishing system for protecting one or more separatehazards, comprising a source of supply of liquid carbon dioxide, pipingextending from said source of supply to the one or more separate hazardsto be protected and including a branch line for each hazard and a headercommon to all of the branch lines, a master valve adjacent the source ofsupply for controlling the flow of carbon dioxide through the header tothe branch lines, and a selector valve in each branch line forcontrolling discharge of carbon dioxide at the hazard served thereby,said master and selector valves each including a seating valve disc, afluid operated power piston connected to the valve disc for moving thesame between its open and closed positions, a power cylinder receivingthe power piston and in open communication at its inner end with theinlet of the valve so as to subject one face of the power piston to thefluid pressure developed in said inlet, a pilot line connecting theouter end of the power cylinder with the piping upstream of the valve, apilot valve in the pilot line having means for normally effecting flowof fluid into the outer end of the power cylinder to cause the valvedisc 'to be seated but being operable to efiect venting of the outer endof the power cylinder to the atmosphere to cause the valve disc to beunseated, and an electric control system operating in response to thedetection of fire at a hazard for efl'ecting actuation of the pilotvalves of the master valve and the selector valve of the involved hazardto cause carbon dioxide to be delivered to the hazard to extinguish thetire.

12. A fire extinguishing system for protecting one or more separatehazards, comprising a source of supply 01' liquid carbon dioxide, pipingextending from said source of supply to the one or more separate hazardsto be protected and including a branch line for each hazard and a headercommon to all 01 the branch lines, a master valve adjacent the source ofsupply for controlling the flow of carbon dioxide through the header tothe branch lines, and a selector valve carbon dioxide at the hazardserved thereby. said master and selector valves each including a seatingvalve disc, a fluid operated power piston connected to the valve samebetween its open and power cylinder receiving the open communication atits inner end with the inlet of the valve so as to subject one face ofthe power piston to the fiuid pressure developed in said inlet,controllable means for selectively creating equalized or differentialfluid pressures in the inlet of the valve and in the power cylinderoutwardly of the power piston to cause the valve to be seated orunseated respectively, and an electric control system operating inresponse to the detection of fire at a hazard for effecting actuation ofthe controllable means of the master valve and the selector valve 01'the involved hazard to cause their valve discs to be unseated to causecarbon dioxide to be discharged to effect extinguishment of the fire andthen to cause their valve discs to be reseated,

13. A flre extinguishing system for protecting one or more separatehazards, comprising a source of supply of liquid carbon dioxide, pipingextending from said source of supply to the one or more separate hazardsto be protected and for each closed positions, a power piston and in ingthe same between its open and closed posiin each branch line forcontrolling discharge of tions, a power cylinder receiving the powerpiston and in open communication at its inner end disc for moving the 1hazard served power cylinder to cause the vvalve disc to be seated butbeing operable to effect venting of the outer end of the power cylinderto the atmosphere to cause the valve disc to be unseated.

15. A flre extinguishing system for protecting one or more separatehazards, comprising an insulated storage tank for liquid carbon dioxide,means for maintaining the liquid carbon dioxide at a constant lowtemperature and its corre'-' sponding low vapor pressure, pipingextending from said tank to the one or more separate hazards to beprotected and including a branch line for each hazard and a headercommon to all of the branch lines, a master valve adjacent the tank forcontrolling the flow of carbon dioxide through the header to the branchlines, and a selector valve in each branch line for controllingdischarge of carbon dioxide at the hazard served thereby, said masterand selector valves each including a seating valve disc, a fluidoperated power piston connected to the valve disc for moving the samebetween its open and closed positions, a power cylinder receiving thepower piston and in open communication at its inner end with the inletof the valve so as to subject one face of the power piston to the fluidpressure developed in said inlet, and controllable means for selectivelycreating equalized r differential fluid pressures in the inlet of thevalve and in the power cylinder outwardly of the power piston to causethe valve disc to be seated or unseated respectively.

16. A fire extinguishing system for protecting one or more separatehazards, comprising an insulated storage tank for liquid carbon dioxide,means for maintaining the liquid carbon dioxide at a constant lowtemperature and its corresponding low vapor pressure, piping extendingfrom said tank to the one or more separate hazards to be protected andincluding a branch line for each hazard and a header common to all ofthe branch lines, a master valve adjacent the tank to the one or moreseparate hazards to be tank for controlling the flow of carbon dioxidethrough the header to the branch lines, and a selector valve in eachbranch line for controlling discharge of carbon dioxide at the hazardserved thereby, said master and selector valves each including a seatingvalve disc, a fluid operated power piston connected to the valve discfor moving the same between its open and closed positions, a. powercylinder receiving the power piston and in open communication at itsinner end with the inlet of the valve so as to subject one face of thepower piston to the fluid pressure developed in-said inlet, a pilot lineconnecting the outer end of the power cylinder with the piping upstreamof the valve, a pilot valve in the pilot linehaving means for normallyeifecting flow of fluid into the outer end of the power cylindertovcause the valve disc to be seated but being operable to effectventing of the outer end of the power cylinder to the atmosphere tocause the valve disc to be unseated, and an electric control systemoperating in response to the detection of fire at a hazard for effectingactuation of the pilot valves of the master valve and the selector valveof the involved hazard to cause carbon dioxide to be delivered to thehazard to extinguish the fire.

1'7. A flre extinguishing system for protecting one or more separatehazards, comprising an insulated storage tank for-liquid carbon dioxide,means for maintaining the liquid carbon dioxide at a constant lowtemperature and its correspondjng low vapor pressure, piping extendingfrom said protected and including a branch line for each hazard and aheader common to all or the branch lines, a master valve adjacent thetank for controlling the flow of carbon dioxide through the header tothe branch lines, and a selector valve in each branch line forcontrolling discharge of carbon dioxide at the hazard served thereby,said master and selector valves each includin a seating valve disc, afluid operated power piston connected to the valve disc for moving thesame between its open and closed positions, a power cylinder receivingthepower piston and in open communication at its inner end with theinlet of the valve so as to subject one face or the power piston to thefluid pressure developed in said inlet, controllable means forselectively creating equalized or differential fluid pressures in theinlet of the valve and in the power cylinder outwardly of the powerpiston to cause the valve disc to be seated or unseated respectively,and an electric control system operating in response to the detection offlre at a hazard ,for effecting actuation of the controllable means ofthe master valve and the selector valve of the involved hazard to causetheir valvediscs to be unseated to cause carbon dioxide to be dischargedto effect e'xtinguishment of the fire and then to cause their valvediscs to be reseated.

18. A flre extinguishing system for protecting one or more separatehazards, comprising an insulated storage tank for liquid carbon dioxide,means for-maintaining the liquid carbon dioxide at a constant lowtemperature and its corresponding low vapor pressure, piping extendingfrom said tank to the one or more separate hazards to be protected andincluding a branch line for each hazard and a header common to all ofthe branch lines, a master valve adjacent the tank for controlling theflow of carbon dioxide through the header to the branch lines, and aselector valve in each branch line for controlling discharge of carbondioxide at the hazard served thereby, said master and selector valveseach including a seatin valve disc, a fluid operated power pistonconnected to the valve disc for moving the samebetween its open andclosed positions, a power cylinder receiving the power piston and inopen communication at its inner end with the inlet of the valve so as tosubject one face of the power piston to the fluid pressure developed insaid inlet, and manually operable control mean for selectively creatingequalized or differential fluid pressures in the inlet of the valve andin the power cylinder outwardly of the power piston to cause the valvedisc to be seated or unseated respectively.

19. A flre extinguishing system for protecting one or more separatehazards, comprising a source of supplyof liquid carbon dioxide, pipingextending from said source of supply to the one or more separate hazardsto be protected and including a branch line for each hazard and a headercommon to all of the branch lines, a master valve adjacent the source ofsupply for controlling the flow of carbondioxide through the header tothe branch lines and a selector valve in each branch line forcontrolling discharge of carbon dioxide at the hazard served thereby,said master and selector valves each including a seating valve disc, afluid operated power piston connected to the valve disc for moving thesame between its open and closed positions, and a power cylinderreceiving the power piston and opening at its inner end into theinletof' the valve so as to subject the inner face or the power pistonto the fluid pressure developed in said inlet, a pilot line connectingthe outer end oi the power cylinder with the piping upstream of thevalve, and a pilot valve in the pilot line having means for normally.eitecting flow of fluid into the outer end of the power cylinder tocause the valve disc to be seated but being operable to effect ventingof the outer end of the power cylinder to the atmosphere to cause thevalve disc to be unseated, said selector valves each having meansoperatively associated with the inner end of their power cylinder andtheir power piston for causing the fluid pressure developed in the inletof the valve to be applied to a portion of the inner face of the powerpiston at a slower rate than fluid pressure is developed in the outerend of the power cylinder through the pilot line and applied to theouter face of the power piston so that the rush of fluid created by theunseating of the valve disc of the master valve will not cause falseoperation of the selector valves.

20. A fire extinguishing system for protecting one or more. separatehazards, comprising a source of supply of liquid carbon dioxide, pipingextending from said source of supply to the one or more separate hazardsto be protected and including a branch line for each hazard and a headercommon to all of the branch lines, a master valve adjacent the source ofsupply for controlling the flow of carbon dioxide through the header tothe branch lines, and a selector valve in each branch line forcontrolling discharge of carbon dioxide at the hazard served thereby,said master and selector valves each including a seating valve disc, afluid operated power piston connected to the valve disc for moving thesame between its open and closed positions, a power cylinder receivingthe power piston and opening at its inner end into the inlet of thevalve so as to subject the inner face of the power piston to the fluidpressure prevailing in said inlet, a pilot line connecting the outer endof the power cylinder with the piping upstream of the valve, a pilotvalve in the pilot line having means for normally effecting fiow offluid into the outer end of the power cylinder to cause the valve discto be seated but being operable to effect venting of the outer end ofthe power cylinder to the atmosphere to cause the valve disc to beunseated, said selector valves each having means operatively associatedwith the inner end of their power cylinder and the power piston forcausing the fiuid pressure developed in the inlet of the valve to beapplied to a portion of the inner face of the power piston at a slowerrate than fluid pressure is developed in the outer end of the powercylinder through the pilot line and applied to the outer face ofthepower piston so that the rush of fluid created by the unseating of thevalve disc of the master valve will not cause false operation of theselector valves, and an electric control system operating in response tothe detection of fire at a hazard for effecting actuation of the pilotvalves or the master valve and the selector valve oi the involved hazardto cause carbon dioxide to be delivered to the hazard to extinguish thefire.

21. A fire extinguishing system, comprising a source of supply of liquidcarbon dioxide, piping extending from said source of supply to a hazardto be protected, a valve in the piping adjacent the source of supply tonormally exclude carbon dioxide from the piping downstream of the valve,a second valve in the piping between the first valve andthe hazard,means for causing both of said valves to open to effect flow of carbondioxide from the source of supply to the hazard and for causing both ofthe valves to close to stop said flow, the closing of both of saidvalves causing liquid carbon dioxide to be trapped in the piping betweenthe valves, and means for venting carbon dioxide vapor from the portionoi the piping between the valves.

22. A fire extinguishing system, comprising a source of supply of liquidcarbon dioxide, piping extending from said source of supply to a hazardto be protected, a valve in the piping adjacent the source of supply tonormally exclude carbon dioxide from the piping downstream of the valve,a second valve in the piping between the first valve and the hazard, andmeans for causing both of said valves to open to effect flow of carbondioxide from the source of supply to the hazard and for causing both ofthe valves to close to stop said flow, the closing of both of saidvalves causing liquid carbon dioxide to be trapped in the piping betweenthe valves, the first mentioned valve having means for efiecting thereturn of trapped liquid carbon dioxide to the source of supply when thevapor pressur of the trapped liquid reaches a predetermined value.

23. A fire extinguishing system, comprising a source of supply of liquidcarbon dioxide, piping extending from said source of supply to a hazardto be protected, a first valve in the piping adiacent the source ofsupply to normally exclude carbon dioxide from the piping downstream ofthe valve, means for opening and closing the first valve, a second valvein the piping between the first valve and the hazard, a piston andcylinder assembly operated by carbon dioxide pressure obtained from theportion 01' the piping located between the valves for opening andclosing the second valve, means for creating equalized carbon dioxidepressures in the cylinder on opposit sides of its piston to hold thesecond valve closed and for creating differential carbon dioxidepressures on opposite sides of the piston in the cylinder to open thesecond valve, and means associated with the piston and cylinder assemblyto prevent a sudden rush of carbon dioxide, caused by the opening of thefirst valve, from creating on opposite sides of the piston in thecylinder a difierential carbon dioxide pressure condition that willefi'ect false opening of the second valve.

CHARLES A. GE'IZ;

